Aerodynamic counterweight



P 1964 D. D- MUSGRAVE AERODYNAMIC COUNTERWEIGHT Filed March 4, 1963 N k m.

United States Patent Office 3,149,531 Patented Sept. 22, 1964 3,149,531 AERODYNAMIC COUNTERWEIGHT Daniel D. Musgrave, 8201 Caraway St., Cabin John, Md. Filed Mar. 4, 1963, Ser. No. 262,791 2 Claims. (Cl. 891.7)

This invention relates to recoilless guns and particularly to a system for countering the reactive force developed when a projectile is fired from such a gun. For convenience the invention will be disclosed as applied to a small portable recoilless gun but it would be equally useful for larger guns. (The term gun as used herein is intended to include both smoothbore and rifled pieces, as recoilless weapons may be either type.)

In all modern armies the principal role of the recoilless gun is defense of the infantry against tanks. For this purpose hollow-charge projectiles are provided and various sizes of recoilless weapons have been developed for use at the platoon, battalion, and group level. These differ in details of construction but not in principle of operation, for all achieve recoillessness in accordance with Newtons third law, by ejecting a mass rearwardly to provide the equal and opposite reaction to projectile momentum.

The ejected mass could be a liquid, 2. gas, a solid, or any combination of these, but modern practice employs gases generated during combustion of the propellant. This is convenient in that the ejected gases are dissipated in a compact zone immediately to the rear of the breech Whereas solid or liquid masses are projected considerable distances rearwardly. But severe disadvantages are inherent in any design ejecting gas alone and efforts have been made to employ solids and semi-solids.

When propellant gas is used as the counterweight the quantity of propellant consumed is considerable. A convenient generalization is that a typical recoilless gun requires five times as much powder to accelerate a given projectile to a given velocity as a closed-breech gun requires to accomplish the same result. The excess consumption is needed to provide sufiicient gas momentum to equalize projectile momentum.

This enormous powder consumption introduces severe operating difiiculties. In a typical environment the firing of a single round raises an immense cloud of dust by action of the high-velocity ejected gases. There is also a loud report and usually an acute flash. While blast, flash and dust are also associated with conventional closedbreech weapons these indications are much more pronounced in the firing of recoilless weapons.

In limited cases it has proven feasible to eject solids or semi-solids. The well-known Davis gun, intended for firing from aircraft at submarines, used Vaseline and lead shot. Powder consumption with such an arrangement is reasonable and, over the open sea, there is practically no restriction on .counterweight ejection. However, recoilless weapons used by ground troops must have a limited and'well-defined counterweight danger area.

In consideration of these circumstances the principal object of this invention is to provide a solid counterweight that can be ejected on a pre-determined path.

Another object is to reduce the powder consumption of recoilless guns by use of a solid counterweight which will not endanger personnel in the vicinity of such guns.

Another object is to reduce the blast, smoke, and dust incidental to firing of recoilless guns.

Another object is to provide a solid counterweight that can serve as a decoy.

Another object is to provide a solid counterweight that- Another object is to provide a solid counterweight which may be disposed of in the direction of the target it desire.

Another object is to provide a solid counterweight having aerodynamic lift surfaces.

These and other objects of the present invention will be apparent from the detailed description hereinafter set forth and from the drawing made a part thereof in which:

FIGURE 1 is a longitudinal section of a recoilless gun and an aerodynamic counterweight which is an embodiment of this invention.

FIGURE 2 is a side view of a projectile of the type used in the gun in FIGURE 1 as it appears in flight.

FIGURE 3 is an rear view of the same projectile as it appears in flight.

FIGURE 4 is a side View of the aerodynamic counterweight of FIGURE 1.

FIGURE 5 is a partial top view of the aerodynamic counterweight of FIGURE 1.

FIGURE 6 is a rear view of the aerodynamic counterweight of FIGURE 2.

'FIGURE 7 is an enlarged view of a portion of FIG- URE 4 with certain elements removed for clarity.

FIGURE 8 is a schematic chart of one method of employing the invention.

FIGURE 9 is an alternate nose cap for the aerodynamic counterweight of FIGURE 1 to contain chemicals or explosives.

FIGURE 10 is an alternate nose cap for the aerodynamic counterweight of FIGURE 1 which incorporates a whistle or other noise-making device.

Referring to the'drawings there is shown in FIGURE 1 a portable recoilless gun comprising a tube 1 having affixed thereto a hand'operated firing mechanism 3 and mechanical trigger 5. The firing mechanism communicates with the bore of tube 1 by way of vent 7. (Various types of firing mechanisms are well known in the art. Either percusion or electric ignition may be employed, and it is not necessary to detail their construction here, as it is well-known.)

The bottom of the tube at approximately the area indicated by numerals 9 may be rested on the shoulder of the person doing the firing, in the well-known manner. (It is not intended to limit the invention to portable guns as it could as well be employed with larger weapons. The gun shown is of the class known as the Panzerfaust and it is merely selected for convenience.)

' Inserted into the front of tube 1 is projectile 11 which has flexible tangential fins 13 adapted for wrapping around shank 15 when positioned within the bore of tube 1. The projectile is shown in detail in FIGURES 2 and 3. Projectile 11 is shown with the profile of an armor-piercing projectile, but other types may be employed, as is customary in the art. a I

Disposed in tube 1 is explosive charge 17 adapted to be initiated by firing mechanism 3. Various types of propellants may be employed, and advantage may be taken of recent improvements in this technology.

Encompassing the rear of tube 1 is carrier 19 which, with airfoils 21, fins 23 and elevators 25 constitute an aerodynamic vehicle. These components are shown in FIGURES 1, 4, 5, and 6. The carrier 19 is adapted for frictional engagement on tube 1 and has an interior hollow compartment 27 in which is inserted a spring 29, a

spring 29 which may be slightly compressed by carrier 19 as it is placed on the rear of tube 1. Charge 17 in turn bears against projectile 11 which is retained in position by the tendency of its fins 13 to expand against the interior of tube 1. (For clarity, the weight, charge and projectile are shown slightly separated in FIG. 1.)

Extending rearwardly from the tip of each wing 21 is support 39 which supports an outboard pivot 41 for one of the elevators 25. Each elevator also has an inboard pivot 41 which is suitably afiixed to carrier 19. Also fixed to carrier 19 is stop 43 which protrudes such a distance as to limit the travel of the elevator downward.

At the trailing edge of each airfoil 21 is located a propellor 45 having a tapered hub 47 and a threaded mounting shaft 49 which engages in a threaded hole 51 in the airfoil. The relative location of each propellor hub 7 and each elevator 35 is such that the hub can contact the elevator as shown at 26 in FIGURE 7, when the propellor shaft 49 is only partly screwed into threaded hole 51 in airfoil 21.

The false nose shown in FIGURE 9 may be fixed to the front of carrier '19 to provide an additional effect. It consists of a payload section 59, containing explosives, or smoke producing chemicals, or illuminating mixtures, and a fuze 57. These devices are well known and need not be explained in detail here.

The false nose 53 shown in FIGURE may be similarly used, but it contains a whistle 55 which is of the well-known type.

Operation The method of aiming and firing the gun is that usually employed, but the counterweight travels in a predetermined path. The gun shown in FIGURE 2 is ready to fire, with its counterweight elevators 25 positioned as shown in FIGURE 7 by action of hubs 47. When propellant 1'7 is ignited by firing mechanism 3 via vent 7, projectile 11 is accelerated forwardly and weight 31 is driven to the rear, compressing'spring 29 until barb 37 protrudes through hole 38.

By this time the projectile has departed from the bore and it is no longer important that the aim of the piece remain undisturbed.

The momentum of weight 31 is now imparted to carrier 19 by way of spring 29 and carrier 19 departs from tube 1. As it does so its airfoils provide lift and its elevators 25 cause it to climb steeply. Although spring 29 tends to expand, barb 37 is engaged in hole 38, and therefore weight 31, spring 29 and carrier 19 travel as a unit. The lag in acceleration of the carrier permits the projectile to be out of the bore before the aerodynamic reaction on the elevators imparts a downward thrust on the gun, which of course, tends to throw it off the target.

Referring now to FIGURE 8 there is shown a schematic chart of the external trajectory of the projectile and the aerodynamic path of the counterweight in a typical firing situation.

A soldier 169 is firing a recoilless gun at a tank 191. The tube of the gun is indicated by numeral 1.

The projectile travels from the gun to the tank along trajectory 1116.

The counterweight leaves the rear of the gun on a curved course 102. Its propellers 45 are rotated by relative movement against the air so that when point 103 is reached they have traveled closer to airfoils 21 and away from elevators 25 by action of threads 49 in threaded hole 51. Hubs 47 move out of contact with elevators 25 and the latter contact stops 43. The aerodynamic counterweight now travels on glide path 104 and strikes the ground at 105.

If noise is desired to cause confusion whistle 53 is afiixed to the carrier.

If other effects, such as smoke, explosion or illumination are desired the false nose shown in FIGURE 9 is used.

The considerable expanse of airfoils 21 permit the carrier to act as a radar decoy.

There is thus disclosed an aerodynamic counterweight which may be projected from a recoilless gun to travel on a predetermined path and land at a chosen position relative to said gun. With such a device, flash, blast and dust will be less than when gas is used as a counterweight.

What I claim is:

1. In a counterweight for rearward ballistic ejection from a recoilless weapon the combination of: an airframe having aerodynamic lift wings and aerodynamic steering means; means for mounting said airframe on said recoilless weapon; a mass positionally disposed at a first position relative to said airframe and movable to a second position relative to said airframe; resilient mean interposed between said mass and said airframe and tending to retain said mass at said first position; detent means on said airframe for retaining said mass at said second position; and means for applying ballistic gases generated within said recoilless weapon against said mass thereby moving said mass from said first position to said second position.

2. In a recoilless weapon in combination: a tube; a projectile positioned for acceleration along the main axis of said tube; a counterweight having aerodynamic lift wings mounted therein and positioned for ballistic acceleration along the main axis of said projectile; pivotable aerodynamic elevators mounted on said wings, airflow responsive propellors rotatably mounted on said wings, each of said propellers having a propeller hub which initially secures the elevator in a bias position and stop means mounted on said counterweight for engaging the elevators in a neutral position whereby the counterweight initially follows a curved trajectory and after the release of the elevator from the bias position, the counterweight follows a glide path; an explosive propellant positionally disposed for exerting thrust in opposite directions upon said projectile and said counterweight; and means for initiating explosion of said propellant.

References Cited in the file of this patent UNITED STATES PATENTS 412,670 Ross Oct. 8, 1339 1,192,586 Waring July 25, 1916 1,277,942 Kaylor Sept. s, 1918 2,247,111 Batchelor June 24, 1941 2,285,574 Dunajefi June 9, 1942 2,938,430 P1011 May 31, 1960 3,103,888 Rosenthal Sept. 17, 1963 FOREIGN PATENTS 125,126 Great Britain Apr. 17, 1917 

1. IN A COUNTERWEIGHT FOR REARWARD BALLISTIC EJECTION FROM A RECOILESS WEAPON THE COMBINATION OF: AN AIRFRAME HAVING AERODYNAMIC LIFT WINGS AND AERODYNAMIC STEERING MEANS; MEANS FOR MOUNTING SAID AIRFRAME ON SAID RECOILLESS WEAPON; A MASS POSITIONALLY DISPOSED AT A FIRST POSITION RELATIVE TO SAID AIRFRAME AND MOVABLE TO A SECOND POSITION RELATIVE TO SAID AIRFRAME; RESILIENT MEANS INTERPOSED BETWEEN SAID MASS AND SAID AIRFRAME AND TENDING TO RETAIN SAID MASS AT SAID FIRST POSITION; DETENT MEANS ON SAID AIRFRAME FOR RETAINING SAID MASS AT SAID SECOND POSITION; AND MEANS FOR APPLYING BALLISTIC GASES GENERATED WITHIN SAID RECOILESS WEAPON AGAINST SAID MASS THEREBY MOVING SAID MASS FROM SAID FIRST POSITION TO SAID SECOND POSITION. 